A chlorofluorocarbon (CFC), a hydrochlorofluorocarbon (HCFC), and the like have hitherto been used as a refrigerant for refrigerating machines. However, such compounds were a compound containing chlorine that is responsible for environmental issues, and hence, investigation has been conducted on a chlorine-free alternative refrigerant, such as a hydrofluorocarbon (HFC), etc. As such a hydrofluorocarbon, compounds represented by, for example, 1,1,1,2-tetrafluoroethane, difluoromethane, pentafluoroethane, and 1,1,1-trifluoroethane (hereinafter referred to as R134a, R32, R125, and R143a, respectively), have been attracting attention, and for example, R134a has been chiefly used in a car air conditioner system. However, even in this HFC, there is a concern about influences from the standpoint of global warming. For example, R134a has a high global warming potential (GWP), and hence, an alternative refrigerant which is suitable for the environmental protection has further been demanded.
As a refrigerant which has a low global warming potential and can be used in a current car air conditioner system or the like, there have been proposed refrigerants having a specified polar structure in a molecule thereof and the like, for example, an unsaturated fluorinated hydrocarbon compound (see, for example, PTL 1), a fluorinated ether compound (see, for example, PTL 2), a fluorinated alcohol compound, a fluorinated ketone compound, etc., and the like. Furthermore, a composition including trans-1,3,3,3-tetrafluoropropene (R1234ze), carbon dioxide, and a third component selected from R32, 1,1-difluoroethane (R152a), fluoroethane (R161), R134a, propylene, propane, and a mixture thereof (see, for example, PTL 3) has been found out.